Optical lens

Abstract

The application provides an optical lens, which has eight lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a second lens with positive optical power, whose image side surface is a convex surface; a third lens with negative optical power, whose object side surface is a concave surface; a fourth lens with positive optical power, whose object side surface is a convex surface; a fifth lens with positive optical power, whose object side surface is a convex surface; a sixth lens with negative optical power, whose image side surface is a concave surface; a seventh lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; and an eighth lens with positive optical power, whose object side surface is a concave surface and whose image side surface is a convex surface. The optical lens provided by the application has one or more advantages, such as miniaturization, long focus, large image surface, large aperture, high imaging quality and the like, through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0002] As people's requirements for driving experience continue to increase, vehicle-mounted optical lenses for automotive applications are more and more widely used in intelligent driving, and the position of vehicle-mounted optical lenses in automotive related industries is constantly improving.

[0003] Advanced Driving Assistance System (ADAS) plays an important role in intelligent driving. It collects environmental information through various lenses matched with sensors to ensure the driving safety of drivers. In addition to requiring the optical lens to have a compact and small profile, as well as high pixel, high resolution and other characteristics, lenses for existing ADAS systems also require the optical lens to be capable of clear imaging under low illumination conditions, so it is necessary to develop an optical lens with good imaging effect. Summary of the Invention

[0004] In view of the above problems, the objective of the present invention is to provide an optical lens that has the advantage of excellent imaging quality.

[0005] The technical solution adopted by the present invention is: An optical lens, wherein the number of lenses with optical power is eight, and the lens sequentially comprises, along an optical axis from an object side to an imaging surface: a first lens with negative optical power, an object-side surface of which is concave, and an image-side surface of which is convex; a second lens with positive optical power, an image-side surface of which is convex; a third lens with negative optical power, an object-side surface of which is concave; a fourth lens with positive optical power, an object-side surface of which is convex; a fifth lens with positive optical power, an object-side surface of which is convex; a sixth lens with negative optical power, an image-side surface of which is concave; a seventh lens with negative optical power, an object-side surface of which is convex, and an image-side surface of which is concave; an eighth lens with positive optical power, an object-side surface of which is concave, and an image-side surface of which is convex; wherein a combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and an effective focal length f of the optical lens satisfy: 0.7 < f2345678 / f < 1.1; a focal length f1 of the first lens and a focal length f8 of the eighth lens satisfy: -10.5 < f1 / f8 < -0.9.

[0006] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2<TTL / f<2.4; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 3.5<TTL / IH<4.4.

[0007] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the maximum field of view FOV of the optical lens satisfy: 1<(IH / 2) / (f×tan(FOV / 2))<1.06; the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15°<FOV / Fno<18°.

[0008] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 0.5<IH / f<0.6; the total optical length TTL of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.51<TTL / (IH / 2) / (FOV / 2)×1°<0.55.

[0009] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 50°<f×FOV / IH<60°; the clear aperture half-diameter d1 of the object-side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 3.7<d1 / (IH / 2) / tan(FOV / 2)<4.8.

[0010] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the curvature radius R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.6<R15 / f<3.6; the curvature radius R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -4.5<R16 / f<-2.9; the curvature radius R15 of the object-side surface of the eighth lens and the curvature radius R16 of the image-side surface of the eighth lens satisfy: -1.1<R15 / R16<-0.1; the curvature radius R15 of the object-side surface of the eighth lens and the curvature radius R16 of the image-side surface of the eighth lens satisfy: -0.8<(R15-R16) / (R15+R16)<0.1.

[0011] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.4 < f12 / f34 < -0.1; the combined focal length f12 of the first lens and the second lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f12 / f56 < 2.1; the combined focal length f34 of the third lens and the fourth lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: -7.2 < f34 / f56 < 0; the combined focal length f12 of the first lens and the second lens and the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.2 < f12 / f2345678 < 2.1.

[0012] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -10.5 < f1 / f < -2.2; the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.8 < f2 / f < 2; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.6; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 2.4; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.9 < f5 / f < 1.3; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -8.5 < f6 / f < -0.7; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2.8 < f7 / f < -0.5; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0.9 < f8 / f < 2.7.

[0013] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the curvature radius R1 of the object-side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.2 < R1 / f < -0.6; the curvature radius R2 of the image-side surface of the first lens and the effective focal length f of the optical lens satisfy: -3.5 < R2 / f < -0.7; the curvature radius R1 of the object-side surface of the first lens and the curvature radius R2 of the image-side surface of the first lens satisfy: 0.3 < R1 / R2 < 0.9; the curvature radius R1 of the object-side surface of the first lens and the curvature radius R2 of the image-side surface of the first lens satisfy: -0.6 < (R1-R2) / (R1+R2) < 0.

[0014] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.74<f2345678 / f<1.04; the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -9.52<f1 / f8<-1.01.

[0015] The optical lens provided by the present invention adopts eight lenses with specific optical powers, and through specific matching of surface shapes and reasonable power distribution, can improve the imaging quality of the optical lens, reduce aberrations, improve the imaging quality of the optical lens, so that the lens has one or more advantages such as miniaturization, long focal length, large image surface, large aperture, and high imaging quality. Description of Drawings

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 2 is an MTF curve diagram of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0019] Figure 4 is an MTF curve diagram of the optical lens in Embodiment 2 of the present invention.

[0020] Figure 5 is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0021] Figure 6 is an MTF curve diagram of the optical lens in Embodiment 3 of the present invention.

[0022] The following specific embodiments will further illustrate the present invention with reference to the above drawings. Detailed Description of the Embodiments

[0023] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0025] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0026] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0027] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0028] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] An optical lens provided in an embodiment of the present invention comprises eight lenses with optical power, which are sequentially a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens along the optical axis from the object side to the imaging surface.

[0031] In some embodiments, the first lens may have negative optical power, the object-side surface thereof is concave, and the image-side surface thereof is convex. The second lens may have positive optical power, the object-side surface thereof may be concave or convex, and the image-side surface thereof is convex. The third lens may have negative optical power, the object-side surface thereof is concave, and the image-side surface thereof may be concave or convex. The fourth lens may have positive optical power, the object-side surface thereof is convex, and the image-side surface thereof may be concave or convex. The fifth lens may have positive optical power, the object-side surface thereof is convex, and the image-side surface thereof may be concave or convex. The sixth lens may have negative optical power, the object-side surface thereof may be concave or convex, and the image-side surface thereof is concave. The seventh lens may have negative optical power, the object-side surface thereof is convex, and the image-side surface thereof is concave. The eighth lens may have positive optical power, the object-side surface thereof is concave, and the image-side surface thereof is convex.

[0032] In some embodiments, the optical lens may further comprise a diaphragm, and the diaphragm may be disposed between the first lens and the second lens. It can be understood that the diaphragm is configured to limit the amount of incident light, so as to adjust the brightness of imaging. When the diaphragm is disposed between the first lens and the second lens, it facilitates the correction of diaphragm aberration.

[0033] In some embodiments, the optical lens may further comprise a filter and a protective glass, and the filter and the protective glass are sequentially disposed between the eighth lens and the imaging surface along the optical axis. The filter is configured to filter out interfering light, so as to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass functions to protect the optical lens, and prevents the photosensitive chip from being damaged to affect the imaging effect of the lens.

[0034] In some embodiments, the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f2345678 / f<1.1. Satisfying the above relational expression, controlling the relationship between the lens group behind the diaphragm and the effective focal length of the optical lens is beneficial to aberration correction, and facilitates overall aberration correction and image quality balance. More specifically, 0.74<f2345678 / f<1.04.

[0035] In some embodiments, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -10.5<f1 / f8<-0.9. Satisfying the above range, by reasonably setting the focal length relationship between the first lens and the last lens, the area of light entering the image plane can be increased while ensuring that as much light as possible enters the system, so as to realize high relative illumination and large image plane imaging of the lens. More specifically, -9.52<f1 / f8<-1.01.

[0036] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2<TTL / f<2.4. Satisfying the above range can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, 2.14<TTL / f<2.21.

[0037] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 3.5<TTL / IH<4.4. Satisfying the above range ensures that the lens has a larger image surface under the condition of the same total length, can be matched with an imaging chip of a larger size to achieve high-definition imaging, and better achieves the balance between the small total length and the large image surface of the lens. More specifically, 3.9<TTL / IH<4.03.

[0038] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the maximum field of view FOV of the optical lens satisfy: 1<(IH / 2) / (f×tan(FOV / 2))<1.06. Satisfying the above range controls the optical lens to have smaller distortion and can provide high-definition imaging effect.

[0039] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15°<FOV / Fno<18°. Satisfying the above range is beneficial to expanding the field of view of the lens and increasing the aperture of the lens, realizing the characteristic of large aperture. More specifically, 16.66°<FOV / Fno<16.68°.

[0040] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 0.5<IH / f<0.6. Satisfying the above range controls the image height and focal length of the optical lens within a reasonable range, helps the optical lens have the characteristic of large image surface, and improves the imaging quality. More specifically, 0.53<IH / f<0.57.

[0041] In some embodiments, the total optical length TTL of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.51<TTL / (IH / 2) / (FOV / 2)×1°<0.55. Satisfying the above range helps control the structural balance among the total length, field of view and image height of the optical lens, and makes the structure of the optical lens more stable on the premise of meeting the design requirements.

[0042] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 50°<f×FOV / IH<60°. When the above range is satisfied, reasonably limiting the relationship among the focal length, the field of view and the image height of the optical lens is conducive to realizing the balance between the large field of view and large target surface imaging of the optical lens. More specifically, 53.29°<f×FOV / IH<55.21°.

[0043] In some embodiments, the clear half-aperture d1 of the object-side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 3.7<d1 / (IH / 2) / tan(FOV / 2)<4.8. When the above range is satisfied, on the premise that the optical lens has a large field of view and a large image height, the front aperture can be reasonably controlled, which is conducive to the miniaturization of the optical lens. More specifically, 4.09<d1 / (IH / 2) / tan(FOV / 2)<4.4.

[0044] In some embodiments, the curvature radius R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.6<R15 / f<3.6; the curvature radius R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -4.5<R16 / f<-2.9; the curvature radius R15 of the object-side surface of the eighth lens and the curvature radius R16 of the image-side surface of the eighth lens satisfy: -1.1<R15 / R16<-0.1; the curvature radius R15 of the object-side surface of the eighth lens and the curvature radius R16 of the image-side surface of the eighth lens satisfy: -0.8<(R15-R16) / (R15+R16)<0.1. When the above range is satisfied, by arranging the eighth lens to have a double-convex surface shape, it is conducive to converging light and correcting the field curvature and distortion of the optical lens at the same time, so as to improve the imaging quality of the optical lens. More specifically, 0.69<R15 / f<3.25; -4.14<R16 / f<-3.19; -1.02<R15 / R16<-0.16; -0.71<(R15-R16) / (R15+R16)<0.02.

[0045] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.4 < f12 / f34 < -0.1; the combined focal length f12 of the first lens and the second lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f12 / f56 < 2.1; the combined focal length f34 of the third lens and the fourth lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: -7.2 < f34 / f56 < 0. Satisfying the above ranges, by reasonably setting the relationship of the combined focal lengths of each lens, it is beneficial for the smooth transition of light, correcting various aberrations of the optical lens, and improving the imaging quality of the optical lens. More specifically, -0.3 < f12 / f34 < -0.2; 0.02 < f12 / f56 < 1.92; -6.62 < f34 / f56 < -0.1.

[0046] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.2 < f12 / f2345678 < 2.1. Satisfying the above range enables the first lens and the second lens of the optical lens to have an appropriate power ratio, allows large-angle light entering the lens to be sufficiently transmitted to the rear optical system, and obtains a larger field of view range and higher relative illumination. More specifically, 1.36 < f12 / f2345678 < 1.94.

[0047] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -10.5 < f1 / f < -2.2. Satisfying the above range, configuring the first lens of the optical lens as a negative power lens can capture large-angle light entering the optical lens and expand the field of view range of the optical lens, while also being beneficial for reducing the sensitivity of the optical lens and realizing the miniaturization design of the optical lens. More specifically, -9.55 < f1 / f < -2.47.

[0048] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.8 < f2 / f < 2. Satisfying the above conditional expression enables the second lens to have the function of converging light. When matched with the negative power of the first lens, it can further converge the light passing through the first lens and reduce the height of peripheral light, which is beneficial for reducing the aperture of the rear lenses, balancing aberrations and improving resolution. More specifically, 0.87 < f2 / f < 1.8.

[0049] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.6. When the above range is satisfied, setting the third lens to have negative optical power can further control the incident angle of light, expand the field of view range of the optical lens, increase the back focal length of the optical lens, avoid interference between the lens and the photosensitive chip, facilitate aberration correction, and further improve the imaging quality of the optical lens. More specifically, -1.35 < f3 / f < -0.66.

[0050] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 2.4. When the above range is satisfied, setting the fourth lens to have positive optical power can further converge light from the first three lenses, correct the aberration introduced by the first three lenses, effectively improve the aberration of the edge field of view, and improve the overall imaging quality of the optical lens. More specifically, 0.95 < f4 / f < 2.23.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.9 < f5 / f < 1.3. When the above range is satisfied, defining that the fifth lens has positive optical power is conducive to light convergence, which can effectively correct chromatic aberration, and perform final correction on the aberration generated by the decentration errors of each lens on the object side, that is, it can reduce the decentration sensitivity of the optical lens and suppress the astigmatism generated by the decentration of each lens on the object side, so as to realize the correction of the aberration of the optical lens and improve the imaging resolution. More specifically, 0.95 < f5 / f < 1.14.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -8.5 < f6 / f < -0.7. When the above range is satisfied, setting the sixth lens to have negative optical power enables large field of view light to rise slowly, changes the parallel beam trend of light to divergent trend, which is conducive to controlling the back focal length of the lens and realizing a large target surface. More specifically, -7.88 < f6 / f < -0.81.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2.8 < f7 / f < -0.5. When the above range is satisfied, it is conducive to expanding the width of the light beam, so that the wide light beam can fully enter the imaging surface of the optical lens, enabling the optical lens to have a wider field of view range and facilitating the realization of high-pixel imaging. More specifically, -2.54 < f7 / f < -0.58.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0.9 < f8 / f < 2.7. When the above range is satisfied, arranging the eighth lens to have positive optical power is conducive to converging light, allowing light to smoothly transition to the rear, reducing the height of light incident on the rear part, slowing the upward trend of light, avoiding light energy loss caused by an excessively large chief ray angle with the chip when large-field-of-view light reaches the imaging surface, which is beneficial for improving the illuminance of the edge field of view, and is conducive to achieving a short total optical length. More specifically, 0.99 < f8 / f < 2.43.

[0055] In some embodiments, the curvature radius R1 of the object-side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.2 < R1 / f < -0.6; the curvature radius R2 of the image-side surface of the first lens and the effective focal length f of the optical lens satisfy: -3.5 < R2 / f < -0.7; the curvature radius R1 of the object-side surface of the first lens and the curvature radius R2 of the image-side surface of the first lens satisfy: 0.3 < R1 / R2 < 0.9; the curvature radius R1 of the object-side surface of the first lens and the curvature radius R2 of the image-side surface of the first lens satisfy: -0.6 < (R1-R2) / (R1+R2) < 0. When the above range is satisfied, the first lens has a meniscus shape, which can lower the requirement for the distance of incident light away from the optical axis, is conducive to reducing the front aperture of the lens, and allows light to smoothly transition inside the lens. More specifically, -1.1 < R1 / f < -0.63; -3.26 < R2 / f < -0.77; 0.32 < R1 / R2 < 0.83; -0.51 < (R1-R2) / (R1+R2) < -0.09.

[0056] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.9 < IH / EPD < 1.1. When the above condition is satisfied, the field of view and luminous flux are balanced, improving the imaging quality of the lens. More specifically, 0.97 < IH / EPD < 1.02.

[0057] In some embodiments, the distance BL on the optical axis from the image-side surface of the eighth lens to the imaging surface and the effective focal length f of the optical lens satisfy: 0.19 < BL / f < 0.44. When the above range is satisfied, the optical lens can be provided with the characteristic of long back focal length, which can meet the arrangement requirement of the rear chip, and reduce the difficulty of assembly and processing.

[0058] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f12 / f < 2.2. When the above range is satisfied, the combined focal length of the first lens and the second lens provides positive optical power for the optical lens, which enables the front lens group of the optical lens to have strong light deflection capability, and is conducive to increasing the field of view angle of the optical lens. More specifically, 1.01 < f12 / f < 1.98.

[0059] In some embodiments, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: -8.8 < f34 / f < -3.1. When the above range is satisfied, the combined focal length of the third lens and the fourth lens provides negative optical power for the optical lens, which can fully diverge light to the fifth lens, reduce the risk of ghosting and improve imaging quality. More specifically, -8.01 < f34 / f < -3.47.

[0060] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 0.9 < f56 / f < 35. When the above range is satisfied, the combined focal length of the fifth lens and the sixth lens provides positive optical power for the optical lens, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. More specifically, 1.02 < f56 / f < 32.04.

[0061] In some embodiments, the optical lens satisfies the following conditional expressions: 19 mm < f < 23 mm; 11 mm < EPD < 12 mm; 40 mm < TTL < 48 mm; 1.7 < Fno < 1.9; 10° < CRA < 22°; 3.8 mm < BL < 9.5 mm; 28° < FOV < 32°; 11 mm < IH < 12 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the f-number of the optical lens, CRA represents the chief ray angle of the optical lens, BL represents the distance on the optical axis from the image side surface of the eighth lens to the imaging surface, FOV represents the maximum field of view of the optical lens, and IH represents the real image height corresponding to the maximum field of view of the optical lens. When the above ranges are satisfied, the optical lens has at least one or more advantages such as miniaturization, long focal length, large aperture, and large target surface. More specifically, 20.24 mm < f < 20.98 mm; 11.24 mm < EPD < 11.66 mm; 44.55 mm < TTL < 45.03 mm; 1.79 < Fno < 1.81; 11.01° < CRA < 20.9°; 4.09 mm < BL < 8.93 mm; 29.99° < FOV < 30.01°; 11.19 mm < IH < 11.41 mm.

[0062] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens is made of plastic, production costs can be effectively reduced. Conversely, when the lens is made of glass, the low dispersion characteristic of glass itself can effectively correct the geometric chromatic aberration of the optical system. The optical lens provided by the present invention can employ an all-glass lens structure, which can reduce dispersion, effectively correct chromatic aberration of the optical lens, and improve image quality.

[0063] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the seventh lens of this invention is an aspherical lens; the first, second, third, fourth, fifth, sixth, and eighth lenses are spherical lenses.

[0064] In various embodiments of the present invention, when an aspherical lens is used, the shapes of each aspherical surface of the optical lens satisfy the following equations: ; Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0065] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Example 1

[0066] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, an aperture ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1, and a protective glass G2.

[0067] Among them, the first lens L1 has negative optical power, its object side S1 is concave, and its image side S2 is convex. The second lens L2 has positive optical power, its object side S3 is convex, and its image side S4 is convex. The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex. The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is concave. The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is concave. The sixth lens L6 has negative optical power, its object side S11 is convex, and its image side S12 is concave. The seventh lens L7 has negative optical power, its object side S13 is convex, and its image side S14 is concave. The eighth lens L8 has positive optical power, its object side S15 is convex, and its image side S16 is convex. The object-side surface S17 and the image-side surface S18 of filter G1 are both planar. The object side S19 and image side S20 of the protective glass G2 are both flat. The imaging plane S21 is a plane.

[0068] The seventh lens L7 is a glass aspherical lens; the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the eighth lens L8 are glass spherical lenses.

[0069] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0070] Table 1-1 The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0071] Table 1-2 Figure 2 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies. Example 2

[0072] Please see Figure 3 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the object side S3 of the second lens L2 is concave; the image side S6 of the third lens L3 is concave; the image side S8 of the fourth lens L4 is convex; the image side S10 of the fifth lens L5 is convex; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0073] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0074] Table 2-1 The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0075] Table 2-2 from Figure 4 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions. Example 3

[0076] Please see Figure 5 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the object side S3 of the second lens L2 is concave; the image side S6 of the third lens L3 is concave; the image side S8 of the fourth lens L4 is convex; the object side S11 of the sixth lens L6 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0077] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0078] Table 3-1 The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0079] Table 3-2 from Figure 6 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0080] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view, the principal ray incident angle CRA at the maximum image height, the maximum field of view FOV, the distance BL from the image side of the eighth lens to the imaging plane on the optical axis, and the value corresponding to each conditional expression in each embodiment.

[0081] Table 4 In summary, the optical lens provided by the present invention uses eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as miniaturization, telephoto, large image plane, large aperture, and high imaging quality.

[0082] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising eight lenses having optical power, characterized in that, It sequentially comprises from the object side to the imaging surface along the optical axis: a first lens with negative refractive power, the object-side surface thereof is a concave surface, and the image-side surface thereof is a convex surface; a second lens with positive refractive power, the image-side surface thereof is a convex surface; a third lens with negative refractive power, the object-side surface thereof is a concave surface; a fourth lens with positive refractive power, the object-side surface thereof is a convex surface; a fifth lens with positive refractive power, the object-side surface thereof is a convex surface; a sixth lens with negative refractive power, the image-side surface thereof is a concave surface; a seventh lens with negative refractive power, the object-side surface thereof is a convex surface, and the image-side surface thereof is a concave surface; an eighth lens with positive refractive power, the object-side surface thereof is a concave surface, and the image-side surface thereof is a convex surface; wherein, the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7<f2345678 / f<1.1; the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -10.5<f1 / f8<-0.

9.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2<TTL / f<2.4; the total optical length TTL of the optical lens and the actual image height IH corresponding to the maximum field of view of the optical lens satisfy: 3.5<TTL / IH<4.

4.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the actual image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the maximum field of view FOV of the optical lens satisfy: 1<(IH / 2) / (f×tan(FOV / 2))<1.06; the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15°<FOV / Fno<18°.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the actual image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 0.5<IH / f<0.6; the total optical length TTL of the optical lens, the actual image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.51<TTL / (IH / 2) / (FOV / 2)×1°<0.

55.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens and the actual image height IH corresponding to the maximum field of view of the optical lens satisfy: 50°<f×FOV / IH<60°; the clear aperture half-diameter d1 of the object-side surface of the first lens, the actual image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 3.7<d1 / (IH / 2) / tan(FOV / 2)<4.

8.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.6 < R15 / f < 3.6; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -4.5 < R16 / f < -2.9; the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -1.1 < R15 / R16 < -0.1; the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -0.8 < (R15-R16) / (R15+R16) < 0.

1.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.4 < f12 / f34 < -0.1; the combined focal length f12 of the first lens and the second lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f12 / f56 < 2.1; the combined focal length f34 of the third lens and the fourth lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: -7.2 < f34 / f56 < 0; the combined focal length f12 of the first lens and the second lens and the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.2 < f12 / f2345678 < 2.

1.

8. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -10.5 < f1 / f < -2.2; the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.8 < f2 / f < 2; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.6; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 2.4; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.9 < f5 / f < 1.3; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -8.5 < f6 / f < -0.7; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2.8 < f7 / f < -0.5; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0.9 < f8 / f < 2.

7.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the radius of curvature R1 of the object-side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.2<R1 / f<-0.6; the radius of curvature R2 of the image-side surface of the first lens and the effective focal length f of the optical lens satisfy: -3.5<R2 / f<-0.7; the radius of curvature R1 of the object-side surface of the first lens and the radius of curvature R2 of the image-side surface of the first lens satisfy: 0.3<R1 / R2<0.9; the radius of curvature R1 of the object-side surface of the first lens and the radius of curvature R2 of the image-side surface of the first lens satisfy: -0.6<(R1-R2) / (R1+R2)<0.

10. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.74<f2345678 / f<1.04; the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -9.52<f1 / f8<-1.01.

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